SRAM Hydraulic on Shimano rotors?

[djbowen99]

I switched over from Ultegra disc to eTap HRD and left the Shimano rotors assuming they would play well together. I'm experiencing serious grinding, pulsing and noise issues. After spending countless hours beleeding, adjusting, centering, test riding, etc i am so over this. Only other thing i can think of is swapping over to SRAM rotors but before i spend the $100 has anyone had luck with SRAM on Shimano rotors (the rotors are the newest models)?

[jeanjacques]

Sram Red hydro PM with XTR RT99 rotor, no problem at all.

[motorapido]

There are a couple of possibilities it could an issue with the pads, as you use the brakes more it will probably settle down as the new pads conform to the part worn discs, Or it may be down to the actual pad material being different, again as the brakes bed in it may settle down and this can take some time.

[hmai18]

Did you properly bed in the new pads?

I've run Rival1 hydro calipers with both RT-99 and RT-86 rotors for 3 seasons of cross and gravel adventures in all sorts of conditions without issue.

[dvq]

If you're going to use a new pad shape you probably need a new rotor, you might be hitting a high spot you haven't hit before.

[djbowen99]

i believe i did bed in properly but these rotors were used with the ultegra group for a few hundred miles first.

[TobinHatesYou]

I’ve tested basically every centerlock rotor available with SRAM HRD calipers. IceTech rotors do tend to judder/pulse and make that turkey gobble sound at lower brake strength. Campy H11 rotors are the worst in terms of noise as the vent design results in a mid-frequency droning noise.

Pay the $100 fo a pair of Centerline X rotors. They have the best vent design of any rotor on the market, specifically engineered to prevent funny whistling noises.

[stockae92]

I only have experience of disc rotor in MTB, and I have no problem running switching between SRAM and Shimano rotors. But the pad has been seen both kinds of rotor since new.

[djbowen99]

I think i found the issue, the pad is making contact with a recessed section of the rotor. it looks like the SRAM caliper/pads sit a tad lower. i thought i screwed up and set them for a 140 disc but they look correct.

[TobinHatesYou]

Correct. That is one of the reasons why you get some judder/noise. The notch on the outer edge of the rotor doesn't help either. Even that long vertical vent that leads to the black alloy carrier is a source of noise because air can escape as the pads pass over it.

[djbowen99]

Ordering SRAM centerlock rotors and new pads now...

The horrid pulsing is only under full braking which makes sense. I really hope new rotors are the fix.

[scale29]

The pad sits in that location on the Shimano caliper too, but I haven’t experienced any noise from mine. Let us know how you get on with the SRAM rotors.

[djbowen99]

The Shimano pads that were on the Ultegra brakes have a beveled edge on the bottom which should be just enough to not cause the issue.

[djbowen99]

So far the SRAM rotors are not causing any issues but I have only done the bedding in with laps around the block. It's pretty clear when viewing them on top of each other that the the indent is likely the culprit on the Shimano rotors. I also saved a few grams which i imagine will decrease once there's some more pad on the rotor.

uploading pictures

[TobinHatesYou]

You are not going to gain a gram in weight from transferring pad material to the rotor.